Recently, printers employing one-component development tend to be required to be further miniaturized and prolonged in their service life. In addition, low-temperature fixing of toners used in the printers has been promoted. Therefore, it is urgently necessary for the toners to have improved stress resistance and excellent fixing property.
PTL 1 discloses an electrostatic developing toner that contains a binder resin, a colorant, and a release agent. The toner has a main peak in a range of from 1,000 through 10,000 and a half value width of 15,000 or less in a molecular weight distribution of tetrahydrofuran (THF)-soluble components in the toner (mainly the binder resin) as measured by gel permeation chromatography (GPC). In addition, the toner contains chloroform-insoluble components in a range of from 5% by mass through 40% by mass. PTL 1 reports that, from these properties, a toner that can be fixed at a low temperature, as well as a toner for image formation having good hot-offset resistance and heat storability can be provided.
However, the toner described in PTL 1 has unsatisfactory stress resistance. Therefore, the problem that the toner is cracked or chipped when used for the one-component development has not been solved.
Thus, conventional toners have the problem as described below. The conventional toners have unsatisfactory stress resistance in spite of excellent fixing property (low-temperature fixing property and hot-offset resistance). Especially in the one-component development in which the toners tend to be subjected to stress, the toners are cracked or chipped, so that a defect in quality (adhesion to a blade or filming on a photoconductor) due to cracking or chipping of the toners is easily occurred.